In the previous article we mentioned two factors affecting the alignment in the low area in zinc-nickel alloy plating process, respectively, sodium hydroxide and zinc concentration, which is analyzed from the point of view of the concentration of the main salt of the plating solution, in fact, there is another factor that affects the low zone of the alignment factor, that is, the concentration of the complexing agent.
Change in complexing agent concentration
Complexing agent is alkaline zinc-nickel plating solution complexing zinc and nickel is an important component, can effectively complex the plating solution of nickel ions and zinc ions, to expand the range of current density, improve the plating solution deep plating ability and dispersion ability, in the normal concentration range of the complexing agent can significantly improve the appearance of the plating layer of the high-electricity zone, especially with the brightener with the plating layer will be obviously detailed, bright.
There have been scientific researchers have done experiments, in the zinc-nickel alloy plating bath temperature of 23 ℃, zinc concentration of 7 g, sodium hydroxide concentration of 120 mL / L when changing the concentration of chromium complexing agent, through the 2 A/20 min Hull tank test piece, measuring Hull tank specimen 18 cm at the thickness of the plating layer in the range of non-normal concentration of the complexing agent will lead to problems with the deposition of plating layer when the concentration of the complexing agent is insufficient, will When the concentration of complexing agent is not enough, it will lead to burning in the high current density area, and when its concentration is too much, it will lead to the reduction of current efficiency in the high electric area.
When its concentration is within the normal range, the thickness of the plated layer in the low-current-density area increases slightly with the increase of the complexing agent, but an overdose can also lead to a decrease in the thickness of the plated layer in the low-current-density area.
When we use Bigely zinc nickel alloy plating additives, we need to keep the complexing agent concentration within a certain range, so as to ensure good alignment in the low current region.
If you are interested in zinc-nickel alloy plating additives, please feel free to contact us.
